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Spruce (Picea spp.)-Tip Blight See: Cedar (Cedrus spp.)- Needle Blight Cause Sirococcus conigenus (formerly Ascochyta piniperda), a fungus. It attacks many conifer including western hemlock; Jeffery, ponderosa, and red pine; and blue and sitka spruce. The ...

Spurge, leafy (Euphorbia esula)-Powdery Mildew Cause The fungus Podosphaera euphorbiae can be found in gardens in western Oregon and Washington. It does not seem to be a debilitating problem as plants continue to grow well despite its presence. Shady loca ...

Squash (Cucurbita spp.)-Alternaria Leaf Blight Cause Alternaria cucumerina, a fungus that overwinters primarily in infected plant debris. Symptoms First, small brown spots are on the oldest leaves, which turn brown to black as the disease progresses. Spot ...

Squash (Cucurbita spp.)-Angular Leaf Spot See: Cucumber (Cucumis sativus)- Angular Leaf Spot ...

Squash (Cucurbita spp.)-Aster Yellows See: Aster- Yellows Cause Candidatus (Ca.) Phytoplasma asteris is spread by leafhoppers. The organism overwinters on wild weed hosts. Aster yellows also affects carrot, lettuce, endive, tomato, parsley, onion, salsify ...

Squash (Cucurbita spp.)-Crown and Foot Rot See: Squash (Cucurbita spp.)- Storage Rots By Cynthia M. Ocamb and Hannah Rivedal Cause Fusarium solani f. sp. cucurbitae (teleomorph: Nectria haematococca) is a problem in summer squash and some pumpkin varietie ...

Squash (Cucurbita spp.)-Curly Top Cause The Beet curly top virus, which is transmitted by the beet leafhopper. Symptoms Young infected plants die almost immediately without showing characteristic symptoms. On older plants, mature leaves gradually yellow a ...

Squash (Cucurbita spp.)-Damping-off Cause The fungi or fungus-like microorganisms, Pythium spp., Fusarium spp., and Rhizoctonia solani, attack many vegetable seedlings including members of the genus Cucurbita. Seedlings are very susceptible to infection j ...

Squash (Cucurbita spp.)-Downy Mildew See: Cucumber (Cucumis sativus)- Downy Mildew ...

Squash (Cucurbita spp.)-Fusarium Wilt Cause The fungus, Fusarium oxysporum f. sp. cucurbitacearum, which lives in soil. Symptoms Plants may wilt slowly as foliage yellows or may wilt suddenly without yellowing. Wilting is most severe during water stress. ...